I created a test website to check performance of Cloudflare DNS. Both websites are exact clones.
1 has DNS via cloudflare (all other services are disabled) while the other is using normal dns (domain via bigrock).
https://imgur.com/a/3xMd2HK (1st image is from cloudflare dns and second is from normal)
While DNS have improved significantly it doesnt result in any improvement in TTFB? TTFB is mostly same or even higher in some cases!
Does the TLS and CONNECT values also depend on dns?
Also for some locations such as India DNS itself take 45 ms but TTFB is 25 ms! How is that possible?